2001 BMW X5 transmission/maf fault

2001 BMW X5
125,000 MILES • 6 CYL • AWD • AUTOMATIC
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BOBANDREE
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eml/dsc/trans ("gear") lights came on simultaneously and remained on while I limped home. Next morning, "service enging soon" on steady, engine rough at startup, smoothed out after few minutes of idle. eml/dsc no longer lit.

BMW dealer scan (didn't reveal code numbers) reported "Mass airflow meter shorted causing fault"

Engine runs smoothly (no repairs yet), trans light on and harsh shift, especially on down shift. Similar shifting when in Steptronic/manual mode.

Is replacing MAF likely to correct this trans shifting characteristic? I'd appreciate also any possible reference to X5 auto trans electronic control and management that may be in public domain to better understand sensible course of action.

Thanks,
bob
Oct 26, 2010 at 7:21 PM
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DOCHAGERTY
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It would be very enlightening if I could see the results of the dealers scan. The reasons why the light is on for the transmission is within the scan data, can you get a photocopy? It is possible the replacement of the air mass meter could correct the issue, I would want all the facts before I pulled the trigger on that one.
Oct 26, 2010 at 7:29 PM
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BOBANDREE
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BMW say that info is sent to their archive center at end of each day and would take 3-6 months to retrieve (this was done just last week) ... blah, blah. In other words, trans fault codes not available.

They say they inserted a food MAF and test drove and reinserted my old one (now I know why it was improperly mounted yesterday!!) to prove the problem. Also claim the trans fault will go away and also no eml light currently because obd hasn't yet compiled enough drive time info since being reset.

What is really going on here?
Oct 27, 2010 at 12:22 PM
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DOCHAGERTY
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I resist calling names. The info we need is at their fingertips, They're just too involved in the system to give a s*%$. Whats going on is a scam to get your $$ If replacement of the MAF is the solution, go to Realoem.com and see what it will cost to have one shipped.
Oct 27, 2010 at 3:53 PM
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BOBANDREE
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Thanks, I figured the scam part out on my own. 5 minutes for me to pull out, examine and properly reseat the MAF and they want to charge $955 to replace it. Even considering their vastly inflated dealer price of 390 for a Bosch MAF, how do they get to 955? I understand the difference between overhead and gouging.

I would really like to know of info on how engine management feeds into auto trans control. I'm not trying to make a profit from this, just want to be an educated consumer.
Oct 27, 2010 at 4:37 PM
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DOCHAGERTY
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I googled "bmw x5 bus communication" and found several reasonable explanations, try that and see if it works for you.
Oct 27, 2010 at 6:03 PM
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DOCHAGERTY
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After reading the response, I realize it may have gotten to you in a confused state (it looks different than the way I typed it in) Hope you got what you need, if not let me know and I will try something that works. (I hope!)
Jan 13, 2011 at 4:42 AM
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BOBANDREE
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Thanks for follow up. No problem for me (I speak computer) as the "garble" (") is merely a substitution technique in xml for a double quote character. Whatever software that took your message, converted your use of quotes to the substitution and then the presentation software failed to reverse out the substitution.

A recycler maf ($100) and 5 minutes of my time fixed the problem. Thanks for your help.
Jan 13, 2011 at 2:49 PM
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DOCHAGERTY
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Thank you for your reply. Come on back if there is anything else we can help you with.
Jan 13, 2011 at 2:58 PM